Sunscreen (SPF 30–50+)

Key points

• 90% of visible skin ageing (fine lines, pigmentation, loss of elasticity) is caused by UV exposure — not chronological ageing
• Broad-spectrum SPF 50 blocks 98% of UVB; SPF 30 blocks 97% — the difference matters most in high-UV environments
• UVA causes ageing and cancer without causing redness — most people underestimate UVA damage from daily indoor-to-outdoor transitions
• Reapply every 2 hours of sun exposure — SPF degrades on the skin after this window regardless of water resistance
• Mineral sunscreens (zinc oxide, titanium dioxide) are photostable and non-comedogenic — better for acne-prone and sensitive skin